It has been previously proposed to apply a coating to a rock surface in a mine by spraying an aqueous emulsion of an organic polymer and causing the emulsion to coagulate to produce a flexible coating in the form of a film or skin on the surface.
Polymers which have been disclosed for this purpose include polyurethanes and polychloroprene. The latter has been described in South African Patent No 8203384.
More recently there has been described in WO 98/58886 a composition comprising two parts. One is an aqueous emulsion of an organic polymer such as the copolymer of ethylene and vinyl acetate. The other part is a cementitious composition capable of absorbing at least its own weight of water. The cementitious composition described is an ettringite-forming composition containing high alumina cement, ordinary Portland cement and anhydrite. In use the two parts are sprayed onto a rock surface of a mine to form a coating. This patent also discloses a dry mixture of solids formed from the cementitious composition and a dried polymer emulsion to which mixture water is added in the mine.